Method of and apparatus for placer-mining.



F. E. HAWKESWORTH.

METHOD OF AND APPARATUS FOR PLACER MINING. APPLICATION FILED FEB- I5.1916.

1,244,203. 7 Patented Oct. 23, 1917.

. e t a g FRANK E. HAWKESWOBTH, 013 LOS ANGELES, CALIFORNIA.

METHOD OF AND APPARATUS FOR PLACER-MINING.

Specification of Letters Patent.

Patented net. as, 191 "2.

Application filed February 15, 1916. Serial No. 78,532. I

To all whom it may concern:

Be it known that I, FRANK E. HAwKEs- WORTH, a citizen of the UnitedStates, residing at Los Angeles, in the county of Los Angeles and Stateof California, have invented a new and useful Method of and Apparatusfor Placer-Mining, of which the following is a specification. I

My invention relates to the art of mining, and particularly to the artof working surface deposits of rare metals, commonly designed as placermines.

The object of my invention is to provide means, first, for working suchdeposits thoroughly so that all the surface earth of the property issystematically removed, worked to extract the precious values, and thenpiled in such a manner that it will not require rehandling or interferein any way with subsequent working of the untouched ground; second, forseparating waste boulders and large stones, tree stumps, brush and otherdebris, from the earth before the process of extraction is started, andfor piling said waste material in such a location that it will notinteferewith the subsequent working; third, for providing a working pitwhich will have continuous and adequate drainage so that. there will beno possibility of its becoming flooded by cloud bursts or heavy rains;fourth, for so operating that a definite trench of considerable size isat all times left between the worked and unworked ground so thatoperations are facilitated and there is no liability of reworking anypart of the property.

To produce these new and useful results, the apparatus illustrateddiagrammatically in the drawing is used. In this drawing, Figure 1 is aplan view, and Fig. 2 is a section on a plane rep-resented by the line m-a; of Fig. 1.

Broadly considered, the apparatus consists of a digging means 11, awaste material separating means 12, a primary conveyor 13, a preciousvalue extracting means 14, a secondary conveyor 15, and a stacker 16.The material is taken from a working bank 17 and delivered to a tailingsbank 18. All the apparatus works in a pit 19 bounded by the banks 17 and18. The apparatus illustrated may be driven by electric power, steam,compressed air, or any other convenient means. No novelty is claimedherein for any one of the above named elements of apparatus, the noveltyresiding in the combination of ele ments and method of working to bemore fully disclosed herein.

The digging means 11 may conveniently be a steam shovel havingaboo1n21and a bucket 22, the whole shovel being self propelling on tractionwheels 23,01 caterpillar tractors or common railroad wheels on railroadtrack suitably laid for the purpose. The shovel cuts material out of theworkingbank 17 and dumps it into the hopper 2-1 of the waste materialseparating means 12 which may be a grizzly or similar piece ofapparatus. The means 12 is mounted on wheels running on a circular track25, or caterpillar tractors or tractionwheels without track, travelingin a like circular direction, and has a chute 26 through which the wastematerial which is separated from the smaller workable portion of theground by the grizzly is dumped on the floor of the pit 19, thismaterial falling on the opposite side of the track 25 from the steamshovel and between the track 25 and the extracting means 14.

The waste material left on the floor of pit 19 is shown at 27 and thelocation thereof is important in that it is in a place where it need notbe later disturbed, as will be further understood hereinafter.

The smaller workable material which passes the waste material separatingmeans 12 is delivered by the primary conveyor 13 to the forward end ofthe precious value extracting'means 14. lhe conveyer 13 is pivoted at apoint 30 in the means 14 and swings about thispoint 30, the track 25, or

may consist of any apparatus or collection" of apparatus which isadapted to remove the values it is desired to obtain from the ma terialdelivered by the conveyor 13. Tn placer workings, the means 14; mayconsist of a crusher with a concentrator, an amalgamator, jigs, orindeed any of the common forms of mining machinery suited to isolate andseparate the gold, or other metals or valuable materials, from thetailgig ings. The values are retained and stored in the shed 31 and thetailings are delivered to I the secondary conveyer 15 which is mountedon the front of the stacking means 16, and from thence to the stacker 16which.

delivers the tailings to the bank 18. The conveyors 13 and 15 are of anyof the well known types.

The stacker 16 is also Well known in the art, being carried with theconveyer 15 on suitable trucks, the parts 14, 15 and 16 moving along thetrack 32. The stacker 16 preferably has two booms 40 and 41 in which areplaced elevating conveyers which carry the tailings to the top of thebank 18.

The method of operation is as follows:

The whole apparatus is arranged on the surface of the fieldapproximately as shown, and starts to excavate from the front and stackin the rear, gradually attaining depth as it proceeds forward until theproper level is reached when it proceeds as in the manner shown anddescribed, having formed the pit by gradual descent, taking materialfrom the working bank 17 and dumping it into the hopper 24, the wastematerial 27 being separated by-the waste material separating means 12.The smaller material is carried by the primary conveyer 13 to theprecious value extracting means 14 in which it is treated to remove thegold or other precious metals and materials contained therein. Thetailings are carried back by the secondary conveyer 15 to the stacker16, the tailings being carried upwardly by the stacker and delivered tothe top of the tailings bank 18. As the digging means 11 progresses inthe direction of the arrow D, the waste material separating means 12 ismoved around in the direction of the arrow E, the working bank 17 beingcut away along the line F-G. When the digging means 11 has completed itscircuit to the front drainage ditch C, the means 14 is moved forward onthe track 32, and the track 25 is lifted and moved forward into theposition shown in dotted lines at H. At the same time the means 14, 15and 16 are moved forward on'the track 32, a forward section of trackbeing laid, and a back section of track being removed as necessity re--quires. The operation of digging out the working bank 17 is thenrepeated along the line 1. It will be seen that the method con- 'sistsin general of excavating a circular are from the front of the pit,separating the values from the material excavated, and piling thetailings inthe rear of the pit, the whole apparatus moving forward inthe direction of the arrow J of Fig. 1. It will further be noted thatthe heavy rocks and debris 27 are piled in such a position that they donot interfere with any of the means 11, 12, 1a, 14,, 15 or 16.

v The apparatus is so I arranged that the garages stacker 16 deliversmaterial in such a manner that the rear ditch B is constantly left open.After the pit has traveled across the length of the property, theapparatus is reversed and a return cut is made, the forward ditch (3being in reality a rear ditch B from a previous excavation. The ditchesB and C serve two purposes. In the first place they prevent anyaccumulation of water in the pit, one ditch or the other serving todrain the water off, depending on the direction in which the landslopes. In the second place they serve to separate the working banks 17and 18 so that there is no danger of reworking any of the tailings.The'operation is a continuous one and need not be worked in anapproximately definite straight line if the configuration of theproperty does not admit of this. J

I claim as my invention 1. In an apparatus for placer mining, a preciousvalue extracting means, means for piling the tailings from said preciousvalue extracting means in the rear of said precious value extractingmeans, a primary conveyer mounted on a pivot at the front of saidprecious value extracting means, the outer end of said primary conveyerswinging in an arc of a circle about said pivot, a circular arc of trackon which the outer end of said primary conveyer is mounted, and adigging means'so placed as to excavate material from in front of saidprecious value extracting means and deliver it to the outer end of-saidprimary conveyer.

' 2. In an apparatus for placer mining, a

precious value extracting means, means for.

piling the tailings from said precious value extracting means in therear of said precious value extracting means, a primary conveyer mountedon a pivot at the front'said precious value extracting means, the outerend of said primary conveyer swinging in an arc of a circle about saidpivot, a digging means so placed as to excavate material from in frontof said precious value extracting means and deliver it to the outer endof said primary conveyer, and large material separating means arrangedto remove heavy and large material from the excavated material before itis passed to said primary conveyer.

3. In an apparatus for placer mining, a precious value extracting means,means for piling the tailings from said precious value extracting meansin the rear of said precious value extractin means, a primary conveyermounted on a pivot at the front of said precious value extracting means,the outer end of said primary conveyer swinging in an arc of a circleabout said pivot, a circular arc of track on which the outer end ofsaid. primary conveyer is mounted, a digging means so placed as toexcavate material from in front of said precious value extracting meansand deliver it to the outer end of said primary conveyer, the largematerial separating means mounted to move on said circular arc of trackand arranged to remove large and heavy material from the excavatedmaterial before it is passed to said prirmary conveyer.

4. In an apparatus for placer mining, a precious value extracting means,means for piling the tailings from said precious value extracting meansin. the rear of said precious value extracting means, a primary conveyermounted on a pivot at the front of said precious vaIue extracting means,the outer end of said primary conveyer swinging in an arc of a circleabout said pivot, a digging means so placed as to excavate material fromin front of said precious value extracting means and deliver it to theouter end of said primary conveyer, large material separating meansarranged to remove heavy and large material from the excavated materialbefore it is passed to said primary conveyer, and means by which saidheavy and large. materialis dumped to the rear and inside of saidcircular arc of track, said primary conveyer being adapted to extendover said dumped heavy material.

5. In an apparatus for placer mining, a precious value extracting means,means for piling the tailings from said precious value extracting meansin the rear of said precious value extracting means, a primary conveyermounted on a pivot at the front of said precious value extracting means,the outer end of said primary conveyer swinging in an arc,

of a circle about said pivot, a circular arc of track on which the outerend of said. primary conveyer is mounted, a digging means so placed asto excavate material mm in front of said precious value extracting meansand deliver it to the outer end of said pri-- mary conveyer, largematerial separating 6. The method of placer mining, which.

consists in digging a pit, removing material from the front of the pit,separating the values from said excavated material, and piling thetailings at the rear of the pit, the

removal of the material from the front of v the pit and the piling ofmaterial at the rear of the pit being carried on in such a manner as toleave a frontand rear drainage ditch having their bottoms on the samelevel as the pit floor, said ditches servmg to separate the tailingsfrom the unexcavated material.

7. The method of placer mining, wh ch consists in digging a pit,removing material from the front of the pit, separating heavy materialfrom the excavated material, piling said heavy material in the bottom ofthe pit, separating the values from saidexcavated material, and pilingthe tailings at the rear of the pit, the removal of material from thefront of the pit and the piling of mate- I rial at the rear of the pitbeing carried on in In testimony whereof, I have hereunto set.

my hand at Los Angeles, California, this 8th day of February, 1916.

FRANK E. HAWKESWORTH.

